The present invention relates to a front air-flow streamlining structure of an automotive vehicle, which is configured to streamline traveling air which flows (comes) in below a vehicle floor from a vehicle front side of the automotive vehicle, for example.
An automotive vehicle receives air resistance which is caused by air's (traveling air's) collision, friction or the like during vehicle traveling. Since this air resistance greatly influences the power performance and the fuel-economy performance of the automotive vehicle, it has been desired to reduce the air resistance by means of a vehicle-body shape, an air-flow streamlining plate or the like.
The air resistance during the vehicle traveling which influences the performances of the automotive vehicle includes one which is caused by turbulence of the side-face air flowing down along a vehicle's side face. This air resistance is generated when the traveling air flows in below a floor of the automotive vehicle and this below-floor traveling air which flows into a front wheel house is disturbed by the rotation of a front wheel and then exhausted toward a vehicle side.
Herein, an example of technologies of restraining the below-floor traveling air from flowing into the front wheel house is disclosed in Japanese Utility-Model Laid-Open Publication No. S63-139182, for example. In a lower structure of an automotive vehicle of this publication document, the flowing direction of the below-floor traveling air is changed downward by a shut-off plate which is provided near a front end of the front wheel house to extend downward, thereby restraining the below-floor traveling air from flowing into the front wheel house.
Further, in a front lower structure of a vehicle disclosed in Japanese Patent Laid-Open Publication No. 2002-308154, the flowing direction of the below-floor traveling air is changed downward by exhausting the traveling air downward from an ejection port through a nozzle from an air introduction port provided at a front bumper, thereby restraining the below-floor traveling air from flowing into the front wheel house.
Meanwhile, a technology of obtaining a down force of vehicle front portion by streamlining the below-floor traveling air, in addition to reducing the air resistance during the vehicle traveling by restraining the below-floor traveling air from flowing into the front wheel house, has been also proposed.
A front air-flow streamlining structure of a vehicle disclosed in Japanese Patent Laid-Open Publication No. 2006-219019, for example, comprises a pocket portion which is enclosed by an air dam extending along a lower edge of a front bumper provided forward of the front wheel house and a deflector extending in a vehicle width direction at a front end of the front wheel house. This pocket portion is configured such that an inward side, in the vehicle width direction, thereof opens, and formed substantially in a fan shape in the bottom view.
Since the traveling air may not easily flow into the pocket portion, the pressure of the inside of the pocket portion becomes smaller than that of the circumference. Accordingly, in the structure of the above-described patent publication, the area having a relatively negative pressure is generated in the pocket portion, so that a strong downward-pressing force, i.e., a strong down force, can be generated at the vehicle front portion.
However, while the front air-flow streamlining structure of the vehicle disclosed in the above-described patent publication is useful to the automotive vehicle having high sporty performances including a vehicle's design, it has a problem in that a wagon type of vehicle having a box-shaped or curve-shaped vehicle's rear portion may not easily balance a (dynamic) lift generated at the vehicle front portion with another (dynamic) lift generated at the vehicle's rear portion. Therefore, there is a concern for this front air-flow streamlining structure that the position of such a wagon type of vehicle may change such that its front goes down, so that the maneuverability and stability may deteriorate, or that the air resistance may increase improperly due to an excessive down force.